Process for preventing and/or removing accumulations of solid matter from oil wells,flow lines, and pipe lines



Patented May 24, 1949 PROCESS FOR PREVENTING AND/ OR RE- MOVINGACCUMULATION S OF SOLID MAT- TER FROM OIL WELLS, FLOW LINES, AND

PIPE LINES LoulsT. Monson, Los Angeles County, Calif., asslgnor toPetrolite Corporation, Ltd., Wilmington, Del., a corporation of DelawareNo Drawing. Application January 2, 1947, Serial No. 719,926

18 Claims. 1

This invention relates to a process for preventing and/or removingaccumulations of solid matter from oil wells and pipe lines, and therebyimproving their productivity and capacity.

In many oil wells, deposits of parafiln, wax, asphaltic and bituminousorganic solids and similar materials accumulate in objectionablequantities on the face of the producing formation, on the screen orliner, or in the pump, the casing or the tubing of the well. Suchdeposits operate to decrease materially the productivity of the wells inwhich they occur. Similarly, deposits of the same character are found insome oil flow lines and oil pipe lines, where they effectively reducethe capacity of the pipes, sometimes to the point where little or nofluid can be passed through such conduits in the normal manner ofoperation.

1 The'accumulations with which this invention is concerned are to bedistinguished at the outset from accumulations of mud solids in the formof mud sheaths, the removal of which is the subject-matter of myco-pending application Serial No. 719,925, filed January 2, 1947. Thepresent deposits quite naturally and frequently contain minorproportions of inorganic materials like sand or shale fragments from theproductive formation, or minor proportions of residual drilling mudsolids of the character of clay or weighting materials. They are,however, essentially organic in character; whereas, drilling mud solidsare essentially inorganic in nature.

Further to distinguish the two types of deposits and the character ofthe respective problems they present, it should be noted that mud solidsare ordinarily deposited in a well, or in or on a geological formationpenetrated by a well, as a result of the drilling operation or somesubsequent servicing operation, like killing the well with mud. Suchman-produced mud deposits or mud sheaths constitute non-recurringdeposits.

- Once such a deposit or sheath has been removed,

e. g., by the process of my companion application, just referred to, itcan never again appear or occur in that well.

On the contrary, the organic deposits, with the removal of which thepresent invention is concerned, are essentially progressive depositsproduced naturally during the operation of the well and its accessories.Whereas the mud sheaths occur only at the geological formationspenetrated during drilling of the well, the present organic deposits mayoccur at the formation, at various levels in the well itself, or atvarious points in the transportation lines reaching from the well to therefinery, including tanks. Their deposition is progressive; or, if theyare removed periodically, they may be said to be recurring. Such removalis usually only intentionally achieved; but in some instances, suchorganic deposits slough oif their supporting metallic structure. In suchinstances, they give the appearance of being recurring, becausecontinuing deposition soon produces a new accumulation of appreciableand detectable proportions.

Although such organic deposits may at times contain minor proportions ofinorganic materials like sand, such inorganic components are notmaterial to the deposition of the organic accumulations, their essentialcharacteristics, or their removal by the process constituting myinvention. In a sense, the minor inorganic constituents are the resultof entrapment by the waxy, sticky, or gummy organic materialconstituting the bulk of the ultimate deposit.

The purpose of removing such deposits is obvious. In some areas, wellsdecline in productivity at a more or less rapid rate, because ofdeposition of such deposits on the face of the producing formation. Insome cases, the decline is sufiiciently rapid that the wells must beserviced in some manner or other at a frequency ranging from severaldays to several weeks. In some instances, the deposition is so slow thatservicing at long intervals is suflicient to maintain the well at asatisfactory level of productivity. The same is true of the variousconduits through which the oil travels from the well to the refinery;and periodic servicing of such elements is also required. The capacityof a conduit of circular cross-section is reduced greatly by suchdeposits, usually well beyond the reduction expected from the ratio ofeffective cross-sectional areas of the conduit and the fouled conduit.Where organic deposits of the present type occur on formation walls,well productivity may fall substantially to zero, especially inlow-pressure fields. Pipe capacities are frequently reduced to a smallfraction of their capacities when clean. Ultimately, of course, suchpipes may be found completely clogged by such deposits. In the case ofpipe lines, the operator may find himself burdened with the cost of a 6"or 8" line, yet benei-lting from a capacity equal to that of a 3" or 4"inc.

The process which constitutes the present invention consists insubjecting such clogging organic deposits of wax, paraflin, asphaltic orbituminous substances and the like, to the action of a chemical reagentof the character described below, to the end that such deposits areremoved from the surfaces to which they were originally adherent. Bymeans of the process, the productivity of wells is restored as is thecapacity of flow lines, pipe lines, traps, tanks, pumps, and otherequipment, through which such oil travels from formation to refinery.

It will be obvious that, if the first minute deposit of such organicmaterials is subjected to my reagent, and if such application of reagentis practised continuously or periodically with sufflcient frequency, theoperation has the appearance of a preventive process rather than acorrective process. In addition, it should be noted that my reagent hasa more real claim to acting as a preventive, in that surfacesefiectively cleaned by its application tend to resist renewed depositionof such materials, and to remain clean and operative for longer periodsthan if the reagent had not been applied. Therefore, I have entitled myprocess as being both a preventive and a corrective one. It mayobviously be applied in either sense, and achieve the same ultimategoal, the improvement of emciency of operation of wells and equipment.In the appended claims, I have used the Word removing. It should beclearly understood that I thereby include the prevention of organicdeposits of the present kind.

The reagent which I employ in practising my process is the heart of thepresent invention. Its composition and characteristics will be describedin detail.

The reagent which I employ in practising my process consists of a basicacylated aminoalcohol in which an acyloxy radical derived from adetergent-forming acid having from 8 to 32 carbon atoms is joined to abasic nitrogen atom by a carbon atom chain, or a carbon atom chain whichis interrupted at least once by an oxygen atom, said acylatedaminoalcohol being used in combination with one or more water-insolubleorganic liquids capable of acting as an oil solvent.

The basic acylated aminoalcohol employed as ingredients of my reagentsmay have molecular weights ranging from 273 to about 4,000, in monomerlcform. The minimum figure is derived by considering the amino-alcoholreactant to be triethanolamine and the acylating agent to be a Caunsaturated monocarboxy acid. To produce a compound of maximum molecularweight, the acylating agent could furnish three C31Hs3CO radicals; theelement, OR, could be times OCmI-Izo; and R" could be a polyaminoalcoholradical, rather than the simple alkanol radical, HOC10H20. Such largestelements add up to produce a product of molecular weight, 4,000, orslightly higher.

I prefer to employ my reagent in the form of a relatively stable aqueousdispersion. By relatively stable aqueous dispersion, I mean one that isnot resolved into its components sponstaneously, on standing forprotracted periods of time, e. g., for more than one hour. However, itmay be employed in undiluted form or dispersed in oil. In general, Ihave found the aqueous dispersions to be somewhat more efiective.Sometimes, such aqueous dispersions will be effective, whereas theundiluted reagent or its non-aqueous dispersion or solution will besubstantially inefl'ective.

The basic acylated aminoalcohol employed as an ingredient of the reagentemployed in the present process, consists of an aceylated aminoalcoholin which an acyloxy radical derived from a detergent-forming acid havingfrom 8 to 32 carbon atoms is joined to a basic nitrogen atom by a carbonatom chain, or a carbon atom chain which is interrupted at least once byan oxygen atom. The aminoalcohols may have more than one amino radical,or, for that'matter, more than one basic amino radical. The compoundsherein contemplated as ingredients of my reagent are well-knowncompounds and are produced by conventional procedures. Stated anotherway, the compounds herein contemplated are esters of aminoalcohols whichmay contain ether linkages as well as more than one amino nitrogen atom.

The phrase basic amino nitrogen atom is used in its conventional sense.(Unsaturated groups, or negative groups, if substituted for one or moreof the hydrogens of ammonia, reduce the basicity of the nitrogen atom toa remarkable degree. In general, the presence of one negative grouplinked on the nitrogen in sufilcient to destroy the ordinary basicproperties." Textbook of Organic Chemistry, Richter, second edition,page 253.)

Reference to an amine and the subsequent amino compounds is intended toinclude the salts and the anhydro base. In instances where water ispresent, the term includes the hydrated base as well. Both the anhydrobase and the hydrated base are obviously present when an aqueous systemis being subjected to the reagent, or when the reagent is used as awater solution or dispersion. (In an aqueous solution of the amine, theanhydro base, 'R--NH2, the hydrated base, R-NI-Ia-OH, and the two ionsare all present." Richter, s. v., page 252.)

As has been previously stated, the reagents contemplated as ingredientsin the compositions employed in the present process, are old and wellknown products. For convenience and for purpose of brevity, reference ismade to the following three U. S. patents to De Groote and Keiser, towit: Nos. 2,324,488, 2,324,489, and 2,324,490, all dated July 20, 1943.Said patents are concerned with processes for breaking water-in-oilemulsions. The demulsifying agent employed is in each instance theresultant derived by reaction between a certain fractional ester and anacylated aminoalcohol. The aminoalcohols described 001- lectively in theaforementioned three patents are used as reactants for combining with afractional acidic ester. Thus, said aminoalcohols must have present analcoholiform hydroxyl as part of an acyl radical, or as part of asubstituent for an amino hydrogen atom. In the instant case, suchaminoalcohols are not employed as reactants, except as to salt formationreactions, and the hydroxyl group is not functional. Thus, one mayemploy, not only the aminoalcohols described in the three aforementionedUnited States patents, but also the obvious analogues in which there isno hydroxyl radical present. Sub sequent reference will be made to thisparticular type and examples will be included.

Aforementioned U. S. Patent No. 2,324,488, describes hydroxylatedacylated amino-ether compounds containing:

(a) A radical derived from a basic hydroxyamino-ether and said radicalbeing of the kind containing at least one amino nitrogen free fromattached aryl and amido-linked acyl radicals; said hydroxyamino-etherradical being further characterized by the presence of at least oneradical derived from a basic hydroxyamine and being attached by at leastone ether linkage to at least one radical selected from the class con-'sisting of glycerol radicals, polyglycerol radicals.

glycol radicals, polyglycol radicals, basic hydroxyamine radicals, amidohydroxyamine radicals, and aryl alkanolamine radicals, said basichydroxyamino-ether radical being characterized by containing notmore-than 60 carbon atoms;

and

(b) An acyl radical derived from a detergentforming monocarboxy acidhaving at least 8 car- .bon atoms and not more than 32 carbon atoms,

said acylated amino-ether being additionally characterized by the factthat said aforementioned acyl radical is a substituent for a hydrogenatom of an alcoholic hydroxyl radical.

Aforementioned U. S. Patent No. 2,324,489 describes hydroxylatedacylated monoamino compounds free from ether linkages, said hydroxylatedacylated amino compounds being of the following type:

acooomn)...

Nor)..."

(H O.C,.H2n)m' in which R.CO represents the oxy-acyl radical derivedfrom a monobasic detergent-formin acid; T represents a member of theclass consisting of hydrogen atoms, non-hydroxyl hydrocarbon radicals,and acylated radicals, obtained 2 2 \NC "H2" (C nHZnN Z) zN in which nrepresents a small whole number varying from 2 to a: is a small wholenumber varying from 0 to 10 Z is a member of the class consisting of H,RCO, R'CO, and D, in which- RCO represents an acyl radical derived froma detergent-forming monocarboxy acid; RCO is an acyl radical derivedfrom a lower-molecularweight carboxy acid having 6 carbon atoms or less;and D is a member of the class consisting of alkyl, hydroxylalkyl,aminoalkyl, and acyloxyalkylene, in which instance the acyl group is amember of the class consisting of RC0 and R'CO; and the acylatedpolyamine is further characterlzed by the fact that there must bepresent a member of the class consisting of (a) Acyloxyalkylene radicalin which the acyl group is RC0; and

(b) Joint occurrence of an amino radical in which the acyl group is RC0and a hydroxyalkyl radical.

A description of certain high molal monocarboxy acids, and moreparticularly, those commonly referred to as detergent-formingmonocarboxy acids, appears in U. S. Patent No. 2,324,490. Forconvenience, the following description is substantially a verbatim formof the same subject-matter as it appears in said patent:

It is well known that certain monocarboxy organic acids containing eightcarbon atoms or more, and not more than 32 carbon atoms, arecharacterized by the fact that they combine with alkyl, hydroxylalkyl,aminoalkyl, and acyloxy- These detergent-forming acids include fattyacids, resin acids, petroleum acids, etc. For the sake of convenience,these acids will be indicated by the formula R.COOH. Certain derivativesof detergent-forming acids react with alkali to produce soap orsoap-like materials, and are the obvious equivalent of the unchanged orunmodified detergent-forming acids. For instance, instead of fattyacids, one might employ the chlorinated fatty acids. Instead of theresin acids, one might employ the hydrogenated resin acids. Instead ofnaphthenic acids, one might employ brominated naphthenic acids, etc.

The fatty acids are of the type commonly referred to as higher fattyacids; and of course, this is also true in regard to derivatives of thekind indicated, insofar that such derivatives are obtained from higherfatty acids. The petroleum acids include not only naturally-occurringnaphthenic acids, but also acids obtained by the oxidation of wax,paraflin, etc. Such acids may have as many as 32 carbon atoms. Forinstance, see U. S. Patent No. 2,242,837, dated May 20, 1941 to Shields.

I have found that the acylated aminoalcohol ingredient of thecomposition of matter herein described and employed in the presentprocess, is preferably derived from unsaturated fatty acids having 18carbon atoms. Such' unsaturated fatty acids include oleic acid,ricinoleic acid, linoleic acid, linolenic acid, etc. One may employmixed fatty acids, as, for example, the fatty acids obtained fromhydrolysis of cottonseed oil,

soyabean oil, etc. The preferred acylated amino- 0 been subjected tooxidation. In addition to synthetic carboxy acids obtained by theoxidation of parafiins or the like, there is the somewhat analogousclass obtained by treating carbon dioxide or carbon monoxide, in thepresence of hydrogen or an olefin, with steam, or by causing ahalogenated hydrocarbon to act with potassium cyanide and saponifyingthe product obtained. Such products or mixtures thereof, having at least8 and not more than 32 carbon atoms and having at least one carboxylgroup, or the equivalent thereof, are suitable as detergent-formingmonocarboxy acids; and another analogous class equally suitable is themixture of carboxylic acids obtained by the alkali treatment of alcoholsof higher molecular weight formed in the catalytic hydrogenation ofcarbon monoxide.

As is well known, one need not use the high molal carboxy acid, such asa fatty acid, for introduction of the acyl group or acyloxy group. Anysuitable functional equivalent such as the acyl halide, the anhydride,ester, amide, etc., may be employed.

The reagent employed in the present process includes an aminoalcoholester, as described; and particular attention is directed to thefactthat, although such esterified aminoalcohol need not contain ahydroxyl radical, my preferred form is the hydroxylated type. Otheraminoalcohol esters of the kind herein contemplated are described in U.S. Patent No. 2,259,704, dated October 21, 1941, to Manson and Anderson.

In light of what has been said, it hardly appears necessary to include alist of reactants and reagents derivable therefrom. However, forconvenience, the following amines are included.

Suitable primary and secondary amines, which may be employed to producematerials of the kind above described, include the following:Diethanolamine, monoethanolamine, ethylethanolamine, methylethanolamine,propanolamine, dipropanolamine, propylpropanolamine, etc. Other examplesinclude cyclohexylolamine, dicyclohexylolamine, cyclohexylethanolamine,cyclohexyl propanolamine, benzylethanolamine, benzylpropanolamine,pentanolamine, hexanolamine, octylethanolamine, octadecylethanolamine,cyclohexanolethanolamine, etc.

Similarly, suitable tertiary amines which may be employed include thefollowing: Triethanolamine, diethanolalkylamines, such asdiethanolethylamine, diethanolpropylamine, etc. Other examples includediethanolmethylamine, tripropanolamine, dipropanolmethylamine,cyclohexanoldiethanolamine, dicyclohexanolethanolamine,cyclohexyldiethanolamine, dicyclohexylethanolamine,dicyclohexanolethylamine, benzyldiethanolamine, benzyldipropanolamine,tripentanolamine, trihexanolamine, hexyldiethanolamine,octadecyldiethanolamine, etc.

Additional amines include ethanoldiethylamine, propanoldiethylamine,ethanoldipropylamine, propanoldipropylamine, dibenzylethanolamine, etc.Ether-type aminoalcohols may be obtained from the above-mentionedaminoalcohols, for example, by treating them with one or more moles ofan oxyalkylating agent, such as ethylene oxide, propylene oxide,butylene oxide, glycid, etc. It is to be noted that comparable productsare obtained by treating primary or secondary amines other thanarylamines with an olefin oxide.

Aminoalcohols containing a primary or secondary amino group, i. e.,having at least one or two amino hydrogen atoms present, may be employedunder especially controlled conditions to give an ester, rather than anamide. One procedure is to permit amidification to take place and thencause a rearrangement to the ester form. See U. S. Patent No. 2,151,788,dated March 28, 1939, to Mauersberger.

AMINOALCOHOL ESTER Example 1 One pound mole of ricinoleic acid isreacted with one pound mole or triethanolamine at approximately 180 to240 C. for approximately to hours, until there is substantially completeesterification.

AMINOALCOHOL ESTER Example 2 Ricinoleic acid in the preceding example isreplaced by methyl naphthenate.

AMINOALCOHOL ESTER Example 3 Methyl abietate is substituted forricinoleic acid in Example 1, preceding.

AMINOALCOHOL ESTER Example 4 Ethyl oleate is substituted for ricinoleicacid in Example 1, preceding.

AMINOALCOHOL ESTER Example 5 One pound mole of triethanolamine isreacted with one pound mole of ethylene oxide and the etherized amine soobtained is substituted for triethanolamine in Examples 1 to 4,preceding.

AMINOALCOHOL ESTER Example 6 One pound mole of triethanolamine isreacted with two pound moles of ethylene oxide and the etherized amineso obtained is substituted for triethanolamine in Examples 1 to 4,preceding.

AMINOALCOHOL ESTER Example 7 One pound mole of triethanolamine isreacted with three pound moles of ethylene oxide, and

' the etherized amine so obtained is substituted for triethanolamine inExamples 1 to 4, preceding.

AMINOALCOHOL ESTER Example 8 One pound mole of triethanolamine isreacted with 4 to 6 pound moles of ethylene oxide and the etherizedamine so obtained is substituted for triethanolamine in Examples 1 to 4,preceding.

AMINOALCOHOL ESTER Example 9 One pound mole of ethanoldiamylamineobtained by reacting one pound mole of diamylamine with one pound moleof ethylene oxide is employed in placed of triethanolamine in Examples 1to 4, preceding.

AMINOALCOHOL ESTER Example 10 The same procedure is employed as in thepreceding example, except that an etherized amine is obtained bytreating diamylamine with 2, 3 or 4 moles of ethylene oxide and suchetherized amine is employed instead of ethanoldiamylamine.

AMINOALCOHOL ESTER Example 11 One pound mole of castor oil is reactedwith 3 pound moles of triethanolamine, as described in theaforementioned U. S. Patent No. 2,324,489, to De Groote and Keiser,under the heading Intermediate hydroxylated amine, Example 1.

AMINOALCOHOL ESTER Example 12 The same procedure is followed as in thepreceding example, except that either one pound mole or two pound molesof gycerol are added to the reaction mass consisting of one pound moleof castor oil and three pound moles, of triethanolamine.

AMINOALCOHOL ESTER Example 13 The resultants obtained in Examples 1 to4, preceding, are treated with equal molal ratios of an olefin oxide.

AMINOALCOHOL ESTER Example 14 One follows the directions of U. S. PatentNo. 2,293,494, to De Groote and Keiser, dated August 18, 1942, toproduce an amine of the following composition:

is substituted for ethylenediaminea' ;oxyethylated ethyienediamineaminomethane;

enough of the olefin oxide, for instance, ethylene AMINOALCOHOL ESTERExample 15 amine is reacted with 4 moles of ethylene. oxide One. poundmole of hydroxyethyl ethylenedito give the correspondingtetrahydroxylated derivative. .Such. compound is employed in place oftriethanolamine in the preceding examples.

AMINOALCOHOL ESTER Example 16 'I he same procedure is iollowed as in thepreceding example, except that 5 to 8 molesof ethylene' oxide areemployed instead of 4 moles.

AMINoALcoHoLE'sTER Example 17 I The same procedure ise nployed a s'inthe preceding example, except that dithylenetriamine AMINOALCOHOL Es EnExample 18' I IAIiH amine of the following composition:

noozrn H1 on ,H CzHcOIEl.

- is substituted for ethylenediamine in the precedingexamples.

AMINOALCOHOL ESTER I Example 19 AMINOALCOHOL ESTER Example 20Unsymmetrical diphenyl diethylenetriamine is treated with ethyleneoxideand substituted for in the preceding examples.

' AMINOALCOHOL ESTER treated with 4 moles of ethylene oxide andsubstituted for 'oxyethylated ethylenediamine in the preceding examples.

AMINOALCOHOL Esrnn Example 22 Additional examples are prepared in themanner previously described, except that one employs aminoalcoholsobtained by the oxyalkylation of morpholine; 1,3-diamino-2-propano1; 2-

- amino-l-butanol; 2-amin'o-2-methyi-l-propanol;

2'-amino-2-methyl-1,3-propanediol; 2 amino-2- ethyl 1,3 propanediol;tris (hydroxymethyl) or piperidine. One may use oxide, to convert allamino hydrogen atoms into hydroxyethyl radicals, or one may employ a 10I greateremount-so as to introduce ether linkages in addition.Ammoatconor. ESTER Example 23 Thel'same procedure is followed as inExample 22, preceding, except that one employs the amines described inExamples 9, 10, 11 and '13 of U. S. Patent No. 2,306,329, to De Grooteand Keiser, dated December 22, 1942.

Amnoanconor. ESTER Example 24 Soyabean oil, blown soyabean oil, blowncastor oil or blown teaseed oil is substituted for castor oil in thepreceding examples.

In; the above Examples it is obvious that free hydroxyl radicals may bepresent as part. of a hydroxyalkyl radical, or as part of the acylradical of a fattty acid such as ricinoleic acid;

' Some of-the acylated aminoalcohols contemplated as ingredients inmyreagent are freely Presumably, such aqueous systems comprise thereagent in the form of a base, i. e.-, a substituted ammonium-compound.In other instances, the free forms of the reagents are substantiallywaterinsoluble, but the salt forms (e. g. the acetates) are verywater-dispersible. I prefer to employ the acylated aminoalcohol inWater-dispersible' form. In some" instances, therefore, it is desirableto neutralize the acylated aminoalcohol to produce a salt which will bewater-dispersible.

I have found, for example, that the acetate, hydroxyacetate, lactate,gluconate, propionate,

caprate, phthalate, fumarate, maleate, benzoate,

succinate,-.oxalate, tartrate, chloride, nitrate, or sulfate, preparedby addition of the suitable acid to the acylated aminoalcohol, usuallyconstitutes a reagent which is somewhat more soluble ordispersible inwater than the original acylated aminoalcohol. It is to be understoodthat references to an acylated aminoalco'hol, in these specificationsand claims, include the reagent in the form of salts, as well as in thefree form and the hy-- drated form.

As an example of a preferred type of acylated aminoalcohol reagent whichis effective as an 1 CIHIOE HOC2H NCzHaOCaHaN HOCQH CQHQOH Afterdetermining the average molecular weight of such mixture, I combine the.same with the ricinoleyl radical by heating it with castor oil in theproportion of 1 pound mole of castor oil for 3 pound moles of the mixedamines, "pound mole in the latter case being calculated on the averagemolecular weight, as determined. Such mixture is heated to approximately-260 C. for approximately 6 to 25 hours, until reaction is complete, asindicated by the disappearance of all of the triricinolein present inthe castor oil. Castor oil is used instead of some other source of thericinoleyl radical, e. g., ricinoleic acid, in

CzHaCCaHtN oimon' leum oil is very effective.

11 the example, because of its ready commercial availability and lowerprice.

Depending upon the choice of acylated amino body and its molecularweight, the solubility may be expected to range from readywater-solubility in the free state substantially to water-insolubility.As stated above, the salts, and specifically the acetates, generallyshow improved watersolubility over the simple acylated amino bodies; andI have obtained the best results by using salt forms of the acylatedamino bodies which possess appreciable water-solubility.

The other component of my reagent is a waterinsoluble organic liquidwhich is capable of acting as an oil solvent. Many materials lendthemselves to this use. One of the commonest is the aromatic fraction ofpetroleum distillates which is quite generally found to disperse theacylated aminoalcohols, mentioned above. Another is the fraction removedfrom distillates by application of the Edeleanu liquid sulfur dioxideextraction process, and which comprises aromatic and unsaturatedcompounds. In some cases, stove oil or similar petroleum distillate isusable. Oil solvents like carbon tetrachloride or carbon disulfide areusable, although their comparatively high cost militates against theiruse. Ainylene dichloride is sometimes a desirable material for thepresent purpose, as are tetrachloroethane, tetralin, trichloroethylene,benzol and its homologues, cyclohexane, etc. This component of myreagent must be water-insoluble and must be an oil solvent. Otherwise,its selection is not limited, although it should be compatible with theother ingredient of my reagent. Naturally, its cost and availabilitywill influence the selection. I prefer to use aromatic petroleumsolvent, as a widely available reagent of low cost and good propertiesfor the present use.

I do not desire to be limited to any specific water-insoluble organicliquid, other than that it shall be capable of acting as an oil solvent.The choice of liquid employed is influenced in part by the bottom-holetemperatures expected to be encountered. The character of the oil beingproduced may also affect the choice. The choice will frequently dependon relative cost of solvents.

I have found that a mixture of organic liquids having the specificproperty of dissolving petro- One such mixture which I have employedcontains benzol, toluol, carbon tetrachloride, tetralin and kerosene.

To prepare my reagent, one simply mixes the two components together insuitable proportions.

The optimum proportion of each will vary, del pending upon itsproperties; but in general, the resulting mixture should be homogeneous.

I also require that the'flnished reagent produce a relatively stableaqueous dispersion in water,

as noted above. In cases where the two ingredients form thoroughlyhomogeneous mixtures, which, however, are not water-dispersible,transformation of the acylated aminoalcohol component into its salt formwill sometimes accomplish this purpose. In such cases, I have preferablyemployed acetic acid to effect this neutralization.

The reagent is prefer bly employed in the form of an aqueous dispersion,although sometimes favorable results are obtained merely by introducingthe undiluted reagentinto the well whose productivity is to be improved.In some of such cases, undoubtedly, there is produced, in the well abore or in the formatiom an aqueous dispersion of the reagent, from'water present in such bore or such formation. Production of an aqueousdispersion from my reagent and water is accomplished almostspontaneously on mixing the two, in most cases. I greatly prefer toemploy the reagent in the form of an aqueous dispersion, because in thatmanner the two components are prevented from separating from each otherbefore the reagent can become efiective to remove the deposit of organicmaterials.

The present reagent has certain advantages over other reagents whichhave been suggested for the same purpose. For example, the presentreagent has been found to be quite stable in the presence of fairlysaline water and in the presence of fairly hard water, over a periodranging from at least several hours to at least several days. Reagentslike those of U. S. Patent No. 1,892,205, to De Groote, dated December2'7, 1932, which in clude sulfonated saponifiable oil, react with hardwater to produce insoluble precipitates of such sulfornated saponifiableoil; and such constituents of such reagents are salted out by salinewaters. The present reagent, in contrast, is unaffected by waters ofappreciable salinity and/or hardness. In fact, as stated above, I havemade it into aqueous dispersions of good stability, using such waters.

It is also noteworthy that my present reagent is useful in the presenceof acids. It may therefore be applied satisfactorily to wells that havebeen acidized by the use of hydrochloric or hydrofiuoric or other acids.The reagents of the abovementioned Patent No. 1,892,205 would react withsuch acidizing acids to liberate free sulfonated fatty acids, whichwould either be water-insoluble per se, or else would readily becomewater-insoluble on hydrolysis and loss of their acid sulfate radical.The present reagent would be quite stable in the presence of suchacidizing acids.

I prefer to employ a considerable excess of acylated aminoalcohol overwhat would be exactly required to effect dispersion of thewaterinsoluble organic liquid in water. Such excess further prevents anyseparation of the phases, enhancing the stability of the dispersion tosuch an extent that it will remain stable for at least several hours.The excess of acylated aminoalcohol also acts to lower the surfacetension of the whole reagent, because of which the reagent exhibits amarked penetrating effect. In this way, it is carried into the crevicesand irregularities of the deposit, weakening the bond between thedeposit of organic materials and the supporting wall. f

The proportions of oil solvent and acylated aminoalcohol may be variedwithin wide limits. For example, I'have prepared my reagent in one formin whichit contained 4 parts of acylated aminoalcohol to 1 part of oilsolvent. I have likewise prepared it ina form in which it contained 4-parts of oil solvent to 1 part of acylated aminoalcohol. Bothformswererelatively stable, and did not separate -appreciably into theircomponents, on standin'g'for protracted periods of time. I have likewiseprepared 'my reagent in a form in which it contained 9 parts ofacylatedaminoalcohol. and 1 part of oil solvent; and in a form in which itcontained l part of acylated aminoalcohol and 9 parts of oil solvent. Ihave thereby determined that use of the acylated aminoalcohol and theoilsolvent within the range be limitedto the exact proportionsofingredients recited in the following example, or to those speclflcingredients recited, the example given being merely illustrative.

As a preferred example of reagent, I employ a dispersion of thepreferred acylated aminoalcohol mentioned above, in aromatic petroleumsolvent, including 2% of concentrated acetic acid in the finishedreagent. I prefer to employ this reagent in the form of a dilute aqueousdispersion;- of about 5% concentration. Sometimes aqueous dispersionscontaining as little as 1% of the reagent are fully effective. Sometimesit is desirable to introduce the reagent in the form of a moreconcentrated aqueous dispersion, as when additional water is expected tobe encountered in the well bore or th surrounding formation. The reagentmay even be introduced in undiluted form, although, as stated above, Iprefer not to use it in this form.

From the foregoing, it will be understood that my invention, broadlystated, consists in subjecth ing a deposit of organic materials of thekind mentioned to the action of a reagent of the kind described. Itshould be understood that while my reagent includes, as an indispensibleingreclient, a constituent which might constitute a wax solvent, it doesnot commonly operate completely to dissolve or completely to disperseany waxy organic deposit to which it may be applied in the practice ofmy invention. Of course, a minor portion of such deposit may be trulydissolved or dispersed by the reagent; but the usual fact is that thedeposit is dislodged and brought to a trap or tank that can be morereadily cleaned of the organic materials. The same statement applies toother types of organic matter which are found in such deposits. Thereagent is usually applied in such small and economical amounts that itcould not dissolve completely, or even satisfactorily, the organicdeposit to which its action is directed. Its manner of operation isuncertain; but its effects are frequently striking. Well productivityusually increases promptly. Line pressures which have increased withdeposition of the organic matter drop to normal within a short time; andsometimes sizeable chunks of the dislodged deposit are'observed in openflows from wells or lines, or on screens inserted into such flows forpurposes of observation. I

My reagent may be applied in a large number of different ways, dependingupon th character of the organic material deposit it is desired toremove and on the location of such deposit. If the productivity of aWell has declined to undesirably low levels and the clogging deposit isfound at the formation, it may be preferable to introduce the reagent,either in undiluted form, or as an aqueous dispersion, into the fluidsbeing produced from the well, and then tie the tubing back into thecasing of the well, and circulate the fluids being produced. In thismanner chemicalized well fluids are passed over the deposit for a periodof from several hours to several days, usually with a strikingimprovement in well productivity when circulation is stopped and normalproduction of the well is resumed.

Sometimes the deposit, is located at\some higher or lower level in thetubing. For example, passage of the well fluids past a point in the wellwhich lies opposite a water sand may produce a deposit at that point,because such a water sand commonly represents a point of cooling. Intreating tubing deposits, the circulation method above may be practised.However, in some instances, it is possible to introduce the reagent inundiluted or diluted form into the tubing at the well head by unscrewingthe stumng box. (Usually the tubing does not stand entirely full offluid, because of slight leakage past the pump.) If the reagent isintroduced as an aqueous dispersion, it will settle relatively slowlydown through the oil in the tubing until it reaches the deposit. Afterintroducing the reagent in any desirable manner, it may be allowed tostand in the tubing for any desired period of time before the well isreplaced on production. In some instances it is preferred to pump thewell intermittently for very short periods of time, so as to pick up thereagent and lift it above the deposit,

letting it settle down past the deposit again during the next idleperiod.

Where th organic deposits in question occur in flow lines, the reagentmay be introduced and allowed to soak the deposit. Thereafter, normalproduction may be resumed; and the dislodged deposit flushed from theline by the flow of well fluids. In other instances, gas pressure is puton the soaked line, and the deposit flushed out in that manner.Sometimes, introduction of a dilute aqueous dispersion of the reagent iseffected intermittently, and the deposit progressively removed. Or thereagent may be introduced in a continuous fashion, if desired.

In the case of pipe lines, the diameter of the pipe and the length ofthe line make it necessary to apply the reagent in the most economicalfashion possible. In such cases, I have found that very dilute aqueousdispersions are useful. e. g., of 1% concentration or sometimes evenless. Soaking of the line, i. e., merely introducing reagent dispersioninto it and allowing the line to lie idle for a period of time, ispracticable. Sometimes I prefer to prepare a relatively large volume ofdilute aqueous dispersion in a tank at some convenient location at oneend of the pipe line, and interrupt the pumping of oil only long enoughto switch to the solution tank and pump .the volume of reagentdispersion into the line. Then the pumping of oil is resumed, and theliquid cylinder of reagent dispersion is thereby moved across the faceof the deposit in the line, over the whole length of line. If desired,the direction of pumping may be reversed when such liquid cylinder ofreagent dispersion reaches the opposite end of the line; and a second,or even a third pass or more may be made, of reagent dispersion over thedeposit in the line.

Where deposits have been allowed to accumulate over a considerableperiod of time, they may be of such proportions that application of anormal amount of my reagent would produce sloughing of suflicient of thedeposit to plug the conduit further downstream, by forming a bridge withundislodged deposit at that point. In such instances, I prefer toproceed more cautiously, introducing successive small portions ofreagent and successively dislodging portions of the deposit sufficientlysmall to pass freely through the limited freeway in the conduit.

Merely introducing my reagent into an area containing a deposit, so thereagent contacts the deposit, is sometimes sufficient to cause theremoval of the latter. Sometimes agitation of the reagent at the face ofthe deposit greatly accelerates removal of the latter. Any suitableagitation means may be employed in such instances.

Because there are so many conditions under which such organic depositsmay occur, it is difficult to give any preferred procedure for applyingmy reagent. The foregoing descriptions have covered instances where suchdeposits were to be removed from the face of the formation, the welltubing or casing, flow lines, and pipe lines. They may be taken aspreferred methods of operating the process for the respective conditionsoutlined. All of them are exemplary only. The process may be varied asconditions may require. In all cases, the process consists broadly inthe application of my reagent to the organic deposits described above.

Application of my reagent upstream in any system, as, for example, intoa well, results in an attack on any such organic deposits furtherdownstream. For example, wax or similar deposits, in traps and tanks,are freed and usually flowed out of such vessels in subsequent operationof the system. In the case of tanks, I have found that waxy tank bottomsmay sometimes be removed by introducing my reagent into the tankcontaining such deposits and allowing the whole to soak for any desiredperiod of time. The deposit is thereby made more free and more readilyremovable. Removal of deposits of organic matter from oil productionequipment, such as traps and tanks and the like, is obviouslycontemplated by my process.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. A process for removing deposits of organic matter from oil wells,flow lines, and pipe lines, which consists in the application thereto 01a reagent comprising a mixture of (a) an acylated derivative of a basicaminoalcohol of the formula:

said derivative being such that there is at least one occurrence of theradical RCO, which is the acyl radical of a monocarboxydetergent-forming acid having at least 8 and not more than 32 carbonatoms; the amino nitrogen atom is basic; R" is a member of the classconsisting of alkanol radicals, aminoalkanol radicals, andpolyaminoalkanol radicals, in which polyaminoalkanol radicals the aminonitrogen atoms are united by divalent radicals selected from the classconsisting of alkylene radicals, alkyleneoxyalkylene radicals,hydroxyalkylene radicals, and hydroxyalkyleneoxyalkylene radicals, andall remaining amino nitrogen valences are satisfied by hydroxyalkylradicals, including those in which the carbon atom chain is interruptedat least once by an oxygen atom; R is an alkylene radical having atleast 2 and not more than 10 carbon atoms; and n is a small whole numbervarying from 1 to 10; RCO being a substituent for a hydroxyl hydrogenatom; and the molecular weight of said compound being at least 273 andnot over 4,000; said amino compound being selected from the classconsisting of the anhydro base, the hydrated base, and salts; and (b) awater-insoluble oil solvent; the proportions of (a) and (b) lyingbetween 1 to 9 and 9 to 1.

2. A process for removing deposits of organic matter from oil wells,flow lines, and pipe lines, which consists in the application thereto ofa relatively stable aqueous dispersion of a reagent comprising a mixtureof (a) an acylated derivative of a basic aminoalcohol of the formula:

said derivative being such that there is at least one occurrence of theradical RCO, which is the acyl radical of a monocarboxydetergent-forming acid having at least 8 and not more than 32 carbonatoms; the amino nitrogen atom is basic; R" is a member of the classconsisting of alkanol radicals, aminoalkanol radicals, andpolyaminoalkanol radicals, in which polyaminoalkanol radicals the aminonitrogen atoms are united by divalent radicals selected from the classconsisting of alkylene radicals, alkylene oxyalkylene radicals,hydroxyalkylene radicals, and hydroxyalkyleneoxyalkylene radicals, andall remaining amino nitrogen valences are satisfied by hydroxyalkylradicals, including those in which the carbon atom chain is interruptedat least once by an oxygen atom; R is an alkylene radical having atleast 2 and not more than 10 carbon atoms; and n is a small whole numbervarying from 1 to 10; RCO being a substituent for a hydroxyl hydrogenatom; and the molecular weight of said compound being at least 273 andnot over 4,000; said amino compound being selected from the classconsisting of the anhydro base, the hydrated base, and salts; and (b) awater-insoluble oil solvent; the proportion of (a) and (b) lying between1 to 9 and 9 to 1.

3. The process of claim 2, wherein the aminoalcohol contains more thanone basic amino nitrogen atom.

4. The process of claim 2, wherein the aminoalcohol contains at least 2and not more than 4 basic amino nitrogen atoms.

5. The process of claim 2, wherein the aminoalcohol contains at least 2and not more than 4 basic amino nitrogen atoms and at least one freehydroxyl radical.

6. The process of claim 2, wherein the aminoalcohol contains at least 2and not more than 4 basic amino nitrogen atoms and a plurality of freehydroxyl radicals.

'7. The process of claim 2, wherein the aminoalcohol contains at least 2and not more than 4 basic amino nitrogen atoms, a plurality of freehydroxyl radicals, and at least one ether radical.

8. The process of claim 2, wherein the aminoalcohol contains at least 2and not more than 4 basic amino nitrogen atoms, a plurality of freehydroxyl radicals, and at least one ether radical in a position otherthan part of the divalent linking radical which unites RCO with thenearest basic amino nitrogen atom.

9. The process of claim 2, wherein the aminoalcohol contains at least 2and not more than 4 basic amino nitrogen atoms, a plurality of freehydroxyl radicals, and at least one ether radical in a position otherthan part of the divalent linking radical which unites RCO with thenearest basic amino nitrogen atom; and wherein RC0 is a higher fattyacid acyl radical.

10. The process of claim 2, wherein the aminoalcohol contains at least 2and not more than 4 basic amino nitrogen atoms, a plurality of freehydroxyl radicals, and at least one ether radical in a position otherthan part of the divalent linking radical which unites RCO with thenearest basic amino nitrogen atom; and wherein RC0 is a higher fattyacid acyl radical having 18 carbon atoms,

11. The process of claim 2, wherein the aminoalcohol contains at least 2and not more than a basic amino nitrogen atoms, a plurality of freehydroxyl radicals, and at least one ether radical in a position otherthan part of the divalent linking radical which unites RCO with thenearest in a position other than part of the divalent linking radicalwhich unites RCO with the nearest basic amino nitrogen atom; and whereinRCO, occurring only once, is an unsaturated higher fatty acid acylradical having 18 carbon atoms.

13. The process of claim 2, wherein the aminoalcohol contains at least 2and not more than 4 basic amino nitrogen atoms, a plurality of freehydroxyl radicals, and at least one ether radical in a position otherthan part of the divalent linking radical which unites RCO with thenearest basic amino nitrogen atom; wherein RCO, occurring only once, isan unsaturated higher fatty acid acyl radical having 18 carbon atoms;and wherein the value of n is unity.

14. The process of claim 2, wherein the aminoalcohol contains at least 2and not more than 4 basic amino nitrogen atoms, a plurality of freehydroxyl radicals, and at least one ether radical in a position otherthan part of the divalent linking v radical which unites RCO with thenearest basic amino nitrogen atom; wherein RCO, occurring only once, isan unsaturated higher fatty acid acyl radical having 18 carbon atoms;and wherein the value of n is unity and R is an alkylene radical havingat least 2 and not more than 3 carbon atoms.

15. The process of claim 2, wherein the aminoalcohol contains at least 2and not more than 4 basic amino nitrogen atoms, a plurality of freehydroxyl radicals, and at least one ether radical in a position otherthan part of the divalent linking radical which unites RCO with thenearest basic amino nitrogen atom; wherein RCO, occurring only once, isan unsaturated higher fatty acid acyl radical having 18 carbon atoms;wherein the value of n is unity and R is an alkylene radical having atleast 2 and not more than 3 carbon atoms; and wherein the molecularweight is less than 1,000.

16. The process of claim 2, wherein the aminoalcohol contains at least 2and not more than 4 basic amino nitrogen atoms, a plurality of freehydroxyl radicals, and at least one ether radical in a position otherthan part of the divalent linking radical which unites RCO with thenearest basic amino nitrogen atom; wherein RCO, occurring only once, isa rlcinoleyl radical; wherein the value of n is unity and R is analkylene radical having at least 2 and not more than 3 carbon atoms; andwherein the molecular weight is less than 1,000.

1'7. The process of claim 2, wherein the aminoalcohol contains at least2 and not more than 4 basic amino nitrogen atoms, a plurality of freehydroxyl radicals, and at least one ether radical in a. position otherthan part of the divalent linking radical which unites RCO with thenearest basic amino nitrogen atom; wherein RCO, occurring only once, isan oleyl radical; wherein the value of n is unity and R is an alkyleneradical having at least 2 and not more than 3 carbon atoms; and whereinthe molecular weight is less than 1,000.

18. The process of claim 2, wherein the aminoalcohol contains at least 2and not more than 4 basic amino nitrogen atoms, a plurality of freehydroxyl radicals, and at least one ether radical in a position otherthan part of the divalent linking radical which unites RCO with thenearest basic amino nitrogen atom; wherein RCO, occurring only once, isa linoleyl radical; wherein the value of n is unity and R is anallcylene radical having at least 2 and-not more than 8 carbon atoms;and wherein the molecular weight is less than 1,000.

LOUIS T. MONSON.

REFERENCES CITED The following references are of record file of thispatent:

UNITED STATES PATENTS in the

